The Neuroproteomics and Neurometabolomics Center on Cell-Cell Signaling (P30DA018310) at the University of Illinois, Urbana-Champaign and Northwestern University with the support of the National Institute on Drug Abuse (NIDA), offer this web site to aid investigators studying proteins present in murine brain tissues. Genetically engineered mice are widely used to model various pathological conditions in mammals. The murine brain is studied to gain insights into the mammalian neuro-proteome and to better understand the molecular mechanisms underlying brain functions. Mouse brain proteoforms (Nature Methods 10, 186-187 2013) contained within this repository have been characterized by top down proteomics experiments. Top down approaches greatly enhance the ability to relate protein modifications to biological activity.